This invention relates to a photoelectric key switch device in which a group of light-receiving elements actuate all together an electric processing circuit.
A photoelectric key switch has been known in the past in which a group each of light-emitting elements and light-receiving elements are disposed on the side of a lock main body so as to oppose one another, while a light transmitting portion and/or light shielding portion is disposed on a key so as to correspond to the arrangement of the light-emitting and light-receiving elements, and when the key is inserted into the lock main body, an electric processing circuit connected to the light-receiving elements is actuated.
In the conventional photoelectric key switch device of the kind described above, however, a light intercepting type rotor is not generally disposed, so that the passage of light from the light-emitting elements to the light-receiving elements is not intercepted. When the key is inserted in the key switch device having such a construction, a group of light transmitting portions and light shielding portion move together with the key, so that the light from the light-emitting elements is repeatedly shielded or transmitted and the electric signal produced from the light-receiving elements does not become constant until the insertion of the key is completed.
Because a minute deviation of position exists between a group of light transmitting portions and light shield portions, it is difficult that the electric signals from a group of light-receiving elements are produced simultaneously. For this reason, the key switch device of this kind is not suitable for electric or electronic appliances which operate only when the electric signals from the group of light-receiving elements are simultaneously applied thereto.